diff --git a/include/fonts/UniCyrExt_8x16.psf b/include/fonts/UniCyrExt_8x16.psf
new file mode 100644
index 0000000..fef3e29
Binary files /dev/null and b/include/fonts/UniCyrExt_8x16.psf differ
diff --git a/include/fonts/UniCyr_8x16.psf b/include/fonts/UniCyr_8x16.psf
deleted file mode 100644
index dcfd01d..0000000
Binary files a/include/fonts/UniCyr_8x16.psf and /dev/null differ
diff --git a/makefile b/makefile
index a7d9edf..39dbc63 100644
--- a/makefile
+++ b/makefile
@@ -26,8 +26,8 @@ PROGRAM_OBJECTS = $(patsubst $(SRC_DIR)/%, $(OBJ_DIR)/%, $(PROGRAM_SOURCES:.c=.o
 TOOLCHAIN_SRC = https://newos.org/toolchains/i386-elf-7.5.0-Linux-x86_64.tar.xz
 TOOLCHAIN_FILE = i386-elf-7.5.0-Linux-x86_64.tar.xz
 
-FONT_OBJ = $(OBJ_DIR)/fonts/UniCyr_8x16.o
-FONT_SRC = $(FONTS_DIR)/UniCyr_8x16.psf
+FONT_OBJ = $(OBJ_DIR)/fonts/UniCyrExt_8x16.o
+FONT_SRC = $(FONTS_DIR)/UniCyrExt_8x16.psf
 
 all: $(OBJ_DIR) kernel.elf programs
 
diff --git a/src/drivers/framebuffer.c b/src/drivers/framebuffer.c
index 0767638..302a723 100644
--- a/src/drivers/framebuffer.c
+++ b/src/drivers/framebuffer.c
@@ -18,13 +18,13 @@ void putpixel(uint32_t* fb, int pitch, int bpp, int x, int y, uint32_t color)
 
 void draw_char(unsigned short int c, int cx, int cy, uint32_t fg, uint32_t bg)
 {
-	PSF_font *font = (PSF_font*)&_binary_include_fonts_UniCyr_8x16_psf_start;
+	PSF_font *font = (PSF_font*)&_binary_include_fonts_UniCyrExt_8x16_psf_start;
 	int bytesperline=(font->width+7)/8;
 	if (unicode != NULL) {
 		c = unicode[c];
 	}
 
-	unsigned char* glyph = (unsigned char*)&_binary_include_fonts_UniCyr_8x16_psf_start + font->headersize + (c>0&&c<font->numglyph?c:0)*font->bytesperglyph;
+	unsigned char* glyph = (unsigned char*)&_binary_include_fonts_UniCyrExt_8x16_psf_start + font->headersize + (c>0&&c<font->numglyph?c:0)*font->bytesperglyph;
 
 	int offs =
 		(cy * font->height * scanline) +
@@ -54,7 +54,7 @@ void scroll()
 {
 	serial_printf(3, "Scrolling...\r");
 	uint32_t bg_color = 0x00000000;
-	PSF_font *font = (PSF_font*)&_binary_include_fonts_UniCyr_8x16_psf_start;
+	PSF_font *font = (PSF_font*)&_binary_include_fonts_UniCyrExt_8x16_psf_start;
 	
 	int line_size = font->height * scanline;
 	int framebuffer_size = scanline * font->height * (1080/font->height);
diff --git a/src/drivers/framebuffer.h b/src/drivers/framebuffer.h
index 84ded03..7786c10 100644
--- a/src/drivers/framebuffer.h
+++ b/src/drivers/framebuffer.h
@@ -9,7 +9,7 @@
 #include <stdint.h>
 
 extern int scanline;
-extern char _binary_include_fonts_UniCyr_8x16_psf_start;
+extern char _binary_include_fonts_UniCyrExt_8x16_psf_start;
 uint16_t* unicode;
 
 #define PIXEL uint32_t
diff --git a/src/kernel/kheap.c b/src/kernel/kheap.c
index 888ed1d..e99bdbe 100644
--- a/src/kernel/kheap.c
+++ b/src/kernel/kheap.c
@@ -56,6 +56,23 @@ void* malloc(size_t size)
 	return NULL;
 }
 
+void* calloc(size_t num, size_t size)
+{
+	size_t total_size = num*size;
+	void* ptr = malloc(total_size);
+
+	if (ptr != NULL)
+	{
+		uint8_t* byte_ptr = (uint8_t*)ptr;
+		for (size_t i=0; i<total_size; i++)
+		{
+			byte_ptr[i] = 0;
+		}
+	}
+
+	return ptr;
+}
+
 void free(void* ptr)
 {
 	if (ptr == NULL) return;
diff --git a/src/kernel/kheap.h b/src/kernel/kheap.h
index f41fa37..2f89ccd 100644
--- a/src/kernel/kheap.h
+++ b/src/kernel/kheap.h
@@ -20,5 +20,6 @@ typedef struct block
 void init_alloc();
 void* malloc(size_t size);
 void free(void* ptr);
+void* calloc(size_t num, size_t size);
 
 #endif
diff --git a/src/kernel/kmain.c b/src/kernel/kmain.c
index 45a1820..5e29e9c 100644
--- a/src/kernel/kmain.c
+++ b/src/kernel/kmain.c
@@ -118,6 +118,10 @@ void kmain(multiboot2_info *mb_info)
     printf("[debug] malloc test ptr1=0x%x, ptr2=0x%x\n", (unsigned int)ptr1, (unsigned int)ptr2); 
     free(ptr1); free(ptr2);
 
+    void* ptr3 = calloc(1024, 2);
+    printf("[debug] calloc test ptr3=0x%x\n", (unsigned int)ptr3);
+    free (ptr3);
+
     // usually the place where i do testing
 
     timer_install();